src/lopcodes.h

   1 /*
   2 ** $Id: lopcodes.h,v 1.125.1.1 2007/12/27 13:02:25 roberto Exp $
   3 ** Opcodes for Lua virtual machine
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #ifndef lopcodes_h
   8 #define lopcodes_h
   9
  10 #include "llimits.h"
  11
  12
  13 /*===========================================================================
  14   We assume that instructions are unsigned numbers.
  15   All instructions have an opcode in the first 6 bits.
  16   Instructions can have the following fields:
  17         `A' : 8 bits
  18         `B' : 9 bits
  19         `C' : 9 bits
  20         `Bx' : 18 bits (`B' and `C' together)
  21         `sBx' : signed Bx
  22
  23   A signed argument is represented in excess K; that is, the number
  24   value is the unsigned value minus K. K is exactly the maximum value
  25   for that argument (so that -max is represented by 0, and +max is
  26   represented by 2*max), which is half the maximum for the corresponding
  27   unsigned argument.
  28 ===========================================================================*/
  29
  30
  31 enum OpMode {iABC, iABx, iAsBx};  /* basic instruction format */
  32
  33
  34 /*
  35 ** size and position of opcode arguments.
  36 */
  37 #define SIZE_C          9
  38 #define SIZE_B          9
  39 #define SIZE_Bx         (SIZE_C + SIZE_B)
  40 #define SIZE_A          8
  41
  42 #define SIZE_OP         6
  43
  44 #define POS_OP          0
  45 #define POS_A           (POS_OP + SIZE_OP)
  46 #define POS_C           (POS_A + SIZE_A)
  47 #define POS_B           (POS_C + SIZE_C)
  48 #define POS_Bx          POS_C
  49
  50
  51 /*
  52 ** limits for opcode arguments.
  53 ** we use (signed) int to manipulate most arguments,
  54 ** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
  55 */
  56 #if SIZE_Bx < LUAI_BITSINT-1
  57 #define MAXARG_Bx        ((1<<SIZE_Bx)-1)
  58 #define MAXARG_sBx        (MAXARG_Bx>>1)         /* `sBx' is signed */
  59 #else
  60 #define MAXARG_Bx        MAX_INT
  61 #define MAXARG_sBx        MAX_INT
  62 #endif
  63
  64
  65 #define MAXARG_A        ((1<<SIZE_A)-1)
  66 #define MAXARG_B        ((1<<SIZE_B)-1)
  67 #define MAXARG_C        ((1<<SIZE_C)-1)
  68
  69
  70 /* creates a mask with `n' 1 bits at position `p' */
  71 #define MASK1(n,p)      ((~((~(Instruction)0)<<n))<<p)
  72
  73 /* creates a mask with `n' 0 bits at position `p' */
  74 #define MASK0(n,p)      (~MASK1(n,p))
  75
  76 /*
  77 ** the following macros help to manipulate instructions
  78 */
  79
  80 #define GET_OPCODE(i)   (cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
  81 #define SET_OPCODE(i,o) ((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
  82                 ((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))
  83
  84 #define GETARG_A(i)     (cast(int, ((i)>>POS_A) & MASK1(SIZE_A,0)))
  85 #define SETARG_A(i,u)   ((i) = (((i)&MASK0(SIZE_A,POS_A)) | \
  86                 ((cast(Instruction, u)<<POS_A)&MASK1(SIZE_A,POS_A))))
  87
  88 #define GETARG_B(i)     (cast(int, ((i)>>POS_B) & MASK1(SIZE_B,0)))
  89 #define SETARG_B(i,b)   ((i) = (((i)&MASK0(SIZE_B,POS_B)) | \
  90                 ((cast(Instruction, b)<<POS_B)&MASK1(SIZE_B,POS_B))))
  91
  92 #define GETARG_C(i)     (cast(int, ((i)>>POS_C) & MASK1(SIZE_C,0)))
  93 #define SETARG_C(i,b)   ((i) = (((i)&MASK0(SIZE_C,POS_C)) | \
  94                 ((cast(Instruction, b)<<POS_C)&MASK1(SIZE_C,POS_C))))
  95
  96 #define GETARG_Bx(i)    (cast(int, ((i)>>POS_Bx) & MASK1(SIZE_Bx,0)))
  97 #define SETARG_Bx(i,b)  ((i) = (((i)&MASK0(SIZE_Bx,POS_Bx)) | \
  98                 ((cast(Instruction, b)<<POS_Bx)&MASK1(SIZE_Bx,POS_Bx))))
  99
 100 #define GETARG_sBx(i)   (GETARG_Bx(i)-MAXARG_sBx)
 101 #define SETARG_sBx(i,b) SETARG_Bx((i),cast(unsigned int, (b)+MAXARG_sBx))
 102
 103
 104 #define CREATE_ABC(o,a,b,c)     ((cast(Instruction, o)<<POS_OP) \
 105                         | (cast(Instruction, a)<<POS_A) \
 106                         | (cast(Instruction, b)<<POS_B) \
 107                         | (cast(Instruction, c)<<POS_C))
 108
 109 #define CREATE_ABx(o,a,bc)      ((cast(Instruction, o)<<POS_OP) \
 110                         | (cast(Instruction, a)<<POS_A) \
 111                         | (cast(Instruction, bc)<<POS_Bx))
 112
 113
 114 /*
 115 ** Macros to operate RK indices
 116 */
 117
 118 /* this bit 1 means constant (0 means register) */
 119 #define BITRK           (1 << (SIZE_B - 1))
 120
 121 /* test whether value is a constant */
 122 #define ISK(x)          ((x) & BITRK)
 123
 124 /* gets the index of the constant */
 125 #define INDEXK(r)       ((int)(r) & ~BITRK)
 126
 127 #define MAXINDEXRK      (BITRK - 1)
 128
 129 /* code a constant index as a RK value */
 130 #define RKASK(x)        ((x) | BITRK)
 131
 132
 133 /*
 134 ** invalid register that fits in 8 bits
 135 */
 136 #define NO_REG          MAXARG_A
 137
 138
 139 /*
 140 ** R(x) - register
 141 ** Kst(x) - constant (in constant table)
 142 ** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
 143 */
 144
 145
 146 /*
 147 ** grep "ORDER OP" if you change these enums
 148 */
 149
 150 typedef enum {
 151 /*----------------------------------------------------------------------
 152 name            args    description
 153 ------------------------------------------------------------------------*/
 154 OP_MOVE,/*      A B     R(A) := R(B)                                    */
 155 OP_LOADK,/*     A Bx    R(A) := Kst(Bx)                                 */
 156 OP_LOADBOOL,/*  A B C   R(A) := (Bool)B; if (C) pc++                    */
 157 OP_LOADNIL,/*   A B     R(A) := ... := R(B) := nil                      */
 158 OP_GETUPVAL,/*  A B     R(A) := UpValue[B]                              */
 159
 160 OP_GETGLOBAL,/* A Bx    R(A) := Gbl[Kst(Bx)]                            */
 161 OP_GETTABLE,/*  A B C   R(A) := R(B)[RK(C)]                             */
 162
 163 OP_SETGLOBAL,/* A Bx    Gbl[Kst(Bx)] := R(A)                            */
 164 OP_SETUPVAL,/*  A B     UpValue[B] := R(A)                              */
 165 OP_SETTABLE,/*  A B C   R(A)[RK(B)] := RK(C)                            */
 166
 167 OP_NEWTABLE,/*  A B C   R(A) := {} (size = B,C)                         */
 168
 169 OP_SELF,/*      A B C   R(A+1) := R(B); R(A) := R(B)[RK(C)]             */
 170
 171 OP_ADD,/*       A B C   R(A) := RK(B) + RK(C)                           */
 172 OP_SUB,/*       A B C   R(A) := RK(B) - RK(C)                           */
 173 OP_MUL,/*       A B C   R(A) := RK(B) * RK(C)                           */
 174 OP_DIV,/*       A B C   R(A) := RK(B) / RK(C)                           */
 175 OP_MOD,/*       A B C   R(A) := RK(B) % RK(C)                           */
 176 OP_POW,/*       A B C   R(A) := RK(B) ^ RK(C)                           */
 177 OP_UNM,/*       A B     R(A) := -R(B)                                   */
 178 OP_NOT,/*       A B     R(A) := not R(B)                                */
 179 OP_LEN,/*       A B     R(A) := length of R(B)                          */
 180
 181 OP_CONCAT,/*    A B C   R(A) := R(B).. ... ..R(C)                       */
 182
 183 OP_JMP,/*       sBx     pc+=sBx                                 */
 184
 185 OP_EQ,/*        A B C   if ((RK(B) == RK(C)) ~= A) then pc++            */
 186 OP_LT,/*        A B C   if ((RK(B) <  RK(C)) ~= A) then pc++            */
 187 OP_LE,/*        A B C   if ((RK(B) <= RK(C)) ~= A) then pc++            */
 188
 189 OP_TEST,/*      A C     if not (R(A) <=> C) then pc++                   */
 190 OP_TESTSET,/*   A B C   if (R(B) <=> C) then R(A) := R(B) else pc++     */
 191
 192 OP_CALL,/*      A B C   R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
 193 OP_TAILCALL,/*  A B C   return R(A)(R(A+1), ... ,R(A+B-1))              */
 194 OP_RETURN,/*    A B     return R(A), ... ,R(A+B-2)      (see note)      */
 195
 196 OP_FORLOOP,/*   A sBx   R(A)+=R(A+2);
 197                         if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
 198 OP_FORPREP,/*   A sBx   R(A)-=R(A+2); pc+=sBx                           */
 199
 200 OP_TFORLOOP,/*  A C     R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));
 201                         if R(A+3) ~= nil then R(A+2)=R(A+3) else pc++   */
 202 OP_SETLIST,/*   A B C   R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B        */
 203
 204 OP_CLOSE,/*     A       close all variables in the stack up to (>=) R(A)*/
 205 OP_CLOSURE,/*   A Bx    R(A) := closure(KPROTO[Bx], R(A), ... ,R(A+n))  */
 206
 207 OP_BAND,
 208 OP_BOR,
 209 OP_BXOR,
 210 OP_BSHL,
 211 OP_BSHR,
 212 OP_BNOT,
 213 OP_VARARG/*     A B     R(A), R(A+1), ..., R(A+B-1) = vararg            */
 214 } OpCode;
 215
 216
 217 #define NUM_OPCODES     (cast(int, OP_VARARG) + 1)
 218
 219
 220
 221 /*===========================================================================
 222   Notes:
 223   (*) In OP_CALL, if (B == 0) then B = top. C is the number of returns - 1,
 224       and can be 0: OP_CALL then sets `top' to last_result+1, so
 225       next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use `top'.
 226
 227   (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
 228       set top (like in OP_CALL with C == 0).
 229
 230   (*) In OP_RETURN, if (B == 0) then return up to `top'
 231
 232   (*) In OP_SETLIST, if (B == 0) then B = `top';
 233       if (C == 0) then next `instruction' is real C
 234
 235   (*) For comparisons, A specifies what condition the test should accept
 236       (true or false).
 237
 238   (*) All `skips' (pc++) assume that next instruction is a jump
 239 ===========================================================================*/
 240
 241
 242 /*
 243 ** masks for instruction properties. The format is:
 244 ** bits 0-1: op mode
 245 ** bits 2-3: C arg mode
 246 ** bits 4-5: B arg mode
 247 ** bit 6: instruction set register A
 248 ** bit 7: operator is a test
 249 */
 250
 251 enum OpArgMask {
 252   OpArgN,  /* argument is not used */
 253   OpArgU,  /* argument is used */
 254   OpArgR,  /* argument is a register or a jump offset */
 255   OpArgK   /* argument is a constant or register/constant */
 256 };
 257
 258 LUAI_DATA const lu_byte luaP_opmodes[NUM_OPCODES];
 259
 260 #define getOpMode(m)    (cast(enum OpMode, luaP_opmodes[m] & 3))
 261 #define getBMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 4) & 3))
 262 #define getCMode(m)     (cast(enum OpArgMask, (luaP_opmodes[m] >> 2) & 3))
 263 #define testAMode(m)    (luaP_opmodes[m] & (1 << 6))
 264 #define testTMode(m)    (luaP_opmodes[m] & (1 << 7))
 265
 266
 267 LUAI_DATA const char *const luaP_opnames[NUM_OPCODES+1];  /* opcode names */
 268
 269
 270 /* number of list items to accumulate before a SETLIST instruction */
 271 #define LFIELDS_PER_FLUSH       50
 272
 273
 274 #endif